Modular power supply arrangement, in particular for reactors for producing polysilicon

ABSTRACT

A power supply arrangement for producing polysilicon with a central control unit and a basic supply unit, which are regulated and controlled by control means. The basic supply unit supplies the supply module with electric energy, an output for connecting to loads which are supplied with electric energy from the mains via basic supply unit, and controllable switches, which are connected to the input and to the output and which are configured for adjusting the energy to be supplied to the loads. The switches are controllable. The control unit is supplied with electric energy. The power supply includes a communication bus. The control module and the basic supply module are connectable to the control module and the basic supply module to the communication bus. The control module and the basic supply module provide connections to the control module and the basic supply module to the communication bus.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a power supply arrangement, inparticular for reactors for producing polysilicon, with a control unitand at least one basic supply unit, wherein the control unit comprisesat least one control and regulating means for controlling and/orregulating the basic supply unit, the basic supply unit comprises, atleast one input for connection to a power mains for supplying electricenergy, at least one output for connecting with a group of loads whichcan be supplied via the basic supply unit with electric energy from thepower mains, and controllable switches, preferably thyristors, which areconnected at least indirectly with the input and at least indirectlywith the output and which are configured for adjusting the energy to besupplied to the loads via the output, wherein the switches can becontrolled by the control unit.

(2) Description of Related Art

A power supply arrangement of this type is known, for example, from thedocument DE 20 2004 014 812 U1. The utility model discloses a powersupply arrangement with a basic supply unit which can be used to supplyan electric voltage to loads connected in series to the power supplyarrangement. A portion of the loads can be supplied in parallel with amedium voltage from a medium voltage supply unit. The control unit isnot described in detail in this document. In particular, it is notdisclosed how the control unit acts on the controllable switches of thebasic supply unit or the medium voltage supply unit.

DE 20 2009 003 325 U1 also describes a power supply arrangement with abasic supply unit and a medium voltage supply unit, wherein the basicsupply unit is not described in detail. A control unit is also mentionedin the document, but not described in detail.

Another disadvantage of this type of power supply arrangement as well asof other power supply arrangements is that they are built individuallyand to order. Each power supply is hence an individual solution for aparticular power supply problem, although experiences from priorsolutions can be relied upon.

BRIEF SUMMARY OF THE INVENTION

It is an object of the invention to improve a power supply arrangementof the aforedescribed type such that starting with a simple power supplyarrangement with a control unit and a basic supply unit, the powersupply arrangements can be flexibly adapted without requiring a newdesign for a particular solution.

This object is attained by the invention in that the control unit is acontrol module and the basic supply unit is a basic supply module, thatthe control module has an input for connection to the power mains forsupplying the control module with electric energy, that the power supplyarrangement includes a communication bus, and that both the controlmodule and the basic supply module include an interface configured forconnecting the control module and the basic supply module to thecommunication bus.

A modular power supply arrangement according to the invention can beflexibly expanded from an arrangement with a control module and a basicsupply module. These expansions may include, for example, additionalbasic supply modules which may optionally be added later to form a powersupply arrangement. The modules to be added are connected to the controlmodule via interfaces and the communication bus to enable control orregulation by the control module. In addition, the modules havededicated inputs for connection to the power mains. The power supplyarrangement of the invention is therefore easily scalable. Accordingly,the power supply arrangement according to the invention can be adaptedto the practical application of producing polysilicon with the Siemensprocess by, for example, matching the number of basic supply modules tothe number of the thin silicon rods to be supplied with power.Optionally, modules can be also be added later to a power supplyarrangement for supplying power to a polysilicon reactor operatingaccording to Siemens process to improve process control. A manufacturerof current supply arrangements or a polysilicon manufacturer can therebyflexibly adapt a facility with Siemens reactors to changing conditions,for example prices for raw material, energy or polysilicon, or changingdemand.

The power supply arrangement may include a transformer with severalsecondary-side taps, wherein each tap of the transformer may beassociated with one input. A group of the controllable switches may beassociated with each input of the basic supply module for adjusting viathis tap the electric energy to be withdrawn from the power mains. Thecontrollable switches may be, for example, thyristors. The groups of thecontrollable switches may advantageously be connected without theinterconnection of additional switches with, on one hand, the taps and,on the other hand, with the output of the basic supply module.Advantageously, in addition to the controllable switches of theaforementioned group, no additional switch, in particular no mechanicalhigh-current switch for safe disconnection, such as a contactor, aredisposed in the current path between the tap and the output.

However, a node may be provided between the groups of the controllableswitches and the output. The node may be connected to a referencepotential via an additional controllable switch. In this way, the outputof the basic supply module can be grounded and short-circuited viaground. This may be desirable if the loads connected to the output of abasic supply module are supplied with electric energy in other ways.Preferably, a basic supply module according to the invention has aninterlock which ensures that either a controllable switch of one of thegroups of the controllable switches or the additional controllableswitch are closed for connection to the reference potential. In thisway, simultaneous supply of electric energy from the basic supply moduleand from other sources to the loads connected to the output of the basicsupply module can be prevented.

At the output of a basic supply module, loads can be supplied with ACvoltages of 0 V to 3000 V, preferably to 2500 V, and with AC currents of0 A to 5000 A, preferably to 4000 A, in particular to 3000 A. Athree-phase AC voltage in the medium voltage range of, for example, 6000V to 33,000 V can be applied to the input of the transformer. Asingle-phase AC voltage of 0 to 3000 V, preferably of 2500 V, may bepresent at the input of the basic supply module.

The basic supply module may include means for identifying a groundfault.

The modular power supply arrangement according to the invention mayinclude several identical or similar basic supply modules.

A modular power supply arrangement of the invention may include as amodule of the different type a medium voltage supply module having atleast one input for connection to a power mains or to the transformerfor supplying electric energy, and outputs for connection to acorresponding load from the group of loads adapted to be supplied fromthe power mains with electric energy, and an interface, by which thepower supply arrangement can be connected to the communication bus.

While the basic supply module supplies at the output of the power supplyarrangement configured to supply power to the connected loads preferablya voltage of 0 V to 2000 V, preferably up to 2500 V, still highervoltages can be provided with a medium voltage supply module. Forexample, AC voltages of 0 V to 12,000 V, in particular to 8000 V, and ACcurrents of 0 A to 50 A, preferably to 20 A, may be provided at theoutputs of the medium voltage supply module.

A medium voltage supply module of a power supply arrangement accordingto the invention can be supplied at its input with a three-phase ACvoltage of 400 V from the power mains or a tap of a transformer. Themedium voltage supply module may include at least one converter forincreasing a voltage supplied at the input. A corresponding convertermay be associated with each output of the medium voltage supply module.

The linked voltage across the outputs may be equal to 0 V at leastduring the time when the loads connected to the output of the mediumvoltage supply module are supplied with electric power. Twocorresponding terminals may be associated with the outputs of the mediumvoltage supply module, wherein with the exception of two outer terminalsall other inner terminals are associated with two outputs. The outerterminals of the medium voltage supply module are each connected with arespective terminal of the output of the basic supply module. The loadscan then be concurrently connected in series to the output of a basicsupply module, without allowing current flow from the medium voltagesupply module to the output of the basic supply module.

The modular power supply arrangement may include several identical orsimilar medium voltage supply modules.

Similar in the context of the specification means that although themedium voltage modules may be different, at least the interfaces to thecommunication bus are identical and each medium voltage supply modulehas a dedicated connection to the grid.

Preferably, the number of medium voltage supply modules corresponds tothe number of basic supply modules. The medium voltage supply modulesand the basic supply modules may each be associated in pairs to acorresponding group of loads.

The modular power supply arrangement of the invention may include amedium frequency supply module which has at least one input forconnection with a power mains or the transformer for supplying electricenergy and outputs for connection to a corresponding load from the groupof loads adapted to be supplied with electric energy from the powermains, and which includes an interface for connecting the power supplyarrangement to the communication bus.

AC voltages of 0 V to 100 V, preferably 50 V, and AC currents of 0 A to1500 A at with frequency of 2 kHz to 250 kHz, preferably from 20 kHz to150 kHz, can be provided at the outputs of the medium frequency supplymodule.

The medium frequency supply module of a modular power supply arrangementmay include one or several frequency converters for changing, inparticular increasing, the frequency of a voltage from the power mainsand supplied at the input.

A corresponding output of the medium frequency supply module may beassociated with each output of one of the frequency converters. Thelinked voltage across a pair of outputs of the medium frequency supplymodules may be equal to 0 V at least when the loads connected to theoutput of the medium frequency supply module are supplied with power.

Two respective terminals may be associated with the outputs of themedium frequency supply module, with each pair of outputs having twoouter terminals and one inner terminal, wherein the outer terminals areassociated with a corresponding one of the two outputs of the pair ofoutputs and the inner terminal is associated with two outputs of thepair of outputs.

A three-phase AC voltage of 200 V to 690 V, preferably of 400 V, can besupplied at the input of the medium frequency supply module between thetwo outer conductors from a power mains or from the transformer.

The modular power supply arrangement may include several identical orsimilar medium frequency supply modules. For connection to thecommunication bus, the similar medium frequency supply modules have atleast interfaces that are identical to those of the other mediumfrequency supply modules, as well as mains connections. The number ofthe medium frequency supply modules may correspond to the number of thebasic supply modules.

Advantageously, in a modular power supply arrangement according to theinvention, the control module, basic supply module and optionally eachmedium frequency supply module are each arranged in a correspondingcontrol cabinet. Each medium voltage supply module may be arranged in acontrol cabinet together with a basic supply module. Each controlcabinet advantageously has a mains connection. Each module may have aconnection to an auxiliary power supply. Each control cabinet mayinclude a display unit, in particular a display screen.

Each module, with the exception of the control module, may have adecentralized control unit which is connected inside the module with,for example, recorders for measured variables, control terminals ofcontrollable switching elements, for example thyristors and the like.The decentralized control units may be connected to the communicationbus via the interfaces of the modules. The decentralized control unitsmay be arranged downstream of the control module.

The power supply arrangement according to the invention is preferablysuitable and configured to supply energy to an even number of loads andhas therefore an even number of outputs.

An exemplary embodiment of a modular power supply arrangement accordingto the invention will now be described with reference to the figures.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 a, b shows a schematic circuit diagram of the modular powersupply arrangement according to the invention, and

FIG. 2 shows a schematic circuit diagram of a modular power supplyarrangement with three basic supply modules.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows the wiring connections of the modular power supplyarrangement according to the invention, as well as a transformer 40, abasic supply module B, a medium voltage supply module MV and a mediumfrequency supply module MF. A control module and a communication bus arenot illustrated. Also not illustrated are the control lines, themeasured value recorder and the measured value lines located inside thebasic supply module B, the medium voltage supply module MV and themedium frequency supply module MF, and the interfaces and interfacedriver circuits of the modules B, MV MF to the communication bus.Likewise, optional control units and/or driver or trigger circuitsoptionally arranged downstream of the control module and disposed in thebasic supply module B, the medium voltage supply module MV and themedium frequency supply module MF are also not shown.

The basic supply module B of the modular power supply arrangementaccording to FIG. 1 includes a mains connection connected to a primaryside of a transformer 40. The secondary side of the transformer 40includes a plurality of first taps 401 to 406. Each of the first taps401 to 406 is connected in the basic supply module B via twoanti-parallel connected thyristors 11 or a triac with a node 12. Thenode 12 is connected, on one hand, to a first terminal 131 of the outputof the basic supply module B. The node 12 can also be connected toground via a controllable switch 141. The second tap 407 of thesecondary side of the transformer 40 is connected to a terminal 132 ofthe output of the basic supply module B and can also be connected toground via a controllable switch 142.

The largest possible voltage drop occurs between the first tap 401 andthe second tap 407 of the secondary side of the transformer 40. Becausethe other first taps 402 to 406 are located between these two taps 401and 407, the voltage drop between one of these first taps 402 to 406 andthe second tap 407 is smaller than the largest possible voltage.Depending on which of the thyristor branches 111 to 116 is conducting, ahigher or lower voltage is provided at the node 12 and hence at theterminal 131, provided that the switch 141 is open. The voltage betweenthe highest possible voltage between the first tap 401 and the secondtap 407 and the smallest voltage between the first tap 406 and thesecond tap 407 can be continuously adjusted by adjusting the firingangle of the thyristors or the phase angle.

A basic supply module B ensures supply of regulated or base load powerto the silicon rods or thin silicon rods R1 to R4 which are connected inseries to the basic supply module B between the terminals 131 and 132.

The output power of a Siemens reactor can be improved with the mediumvoltage supply module MV and the medium frequency supply module MF.Accordingly, the medium voltage supply module MV and the mediumfrequency supply module MF may be provided additionally in the modularswitching arrangements.

The silicon rods or thin silicon rods R1 to R4 supplied with currentfrom the basic supply module B are insulators at low temperatures, i.e.,even at room temperature. The silicon rods or thin silicon rods R1 to R4become conducting only through heating. The medium voltage supply moduleMV can be used to heat the silicon rods or thin silicon rods R1 to R4 atthe beginning of the deposition process, so that they become conductingand can be supplied with current from the basic supply module B(dielectric heating). For this purpose, the outputs of the mediumvoltage supply module B supply higher voltages than the basic supplymodule B. A respective one of the silicon rods or thin silicon rods R1,R2, R3, R4 is connected at each of the outputs. Preferably, the mediumvoltage provided at the outputs has also a higher frequency of, forexample, 5 kHz, than the mains frequency.

The medium voltage supply module MV shown in FIG. 1 has a total of threeconverters 20 which can be used to generate from a three-phase mainsvoltage a voltage with higher frequency. This voltage is thenupconverted by the transformers 21 to a higher voltage of, for example,up to 12 kV. This medium voltage which has a higher frequency than themains voltage is then supplied at the outputs of the medium voltagesupply module MV. A respective one of the silicon rods or thin siliconrods R1, R2, R3, R4 is connected at each of the outputs.

The outputs 23 of the medium voltage supply module MV are linked withone another. For this reason, only five terminals 231 to 235 areprovided for the illustrated four outputs. Of these five terminals, theterminals 232, 233 and 234 are used for two respective consecutiveoutputs of the chain, whereas the terminals 231 and 235 are used for oneoutput located at the beginning and an end of the chain of outputs.

The voltages at the outputs of the medium voltage supply module MV areset so that the voltage drop across the entire chain of the outputs 23is equal to 0 V. Accordingly, there is no voltage drop between theterminals 231 and 235 during operation of the medium voltage supplymodule MV. Because these terminals 231 and 235 are also located at theend of the series connection of the silicon rods or thin silicon rods R1to R4 and because this series connection is connected to the output of abasic supply module B, there is no voltage present at the output of thebasic supply module B which is generated by the medium voltage supplymodule MV during the operation of the medium voltage supply module MV.

Unlike the medium voltage supply module MV, the medium frequency supplymodule MF is used to supply a current to the silicon rods or thinsilicon rods R1, R2, R3, R4 simultaneously with the basic supply moduleB. The medium frequency supply module MF provides at its outputs 34 avoltage with a higher frequency than the mains voltage or the outputvoltage of the basic supply module B.

The medium frequency supply module MF has two three-phase mainsconnections. Each of these mains connections is connected inside themedium frequency supply module MF to a corresponding frequencyconverter. Each frequency converter has two stages 31, 32. The firststages 31 convert the mains voltages to a corresponding DC voltage. TheDC voltages are converted in the second stages 32 of the frequencyconverter to the higher-frequency AC voltages. These high-frequency ACvoltages are supplied to the primary sides 331 of correspondingtransformers 33. The magnetic flux in each of the transformers 33 passeson the secondary side through two coils 332. The secondary coils 332 ofeach of the two transformers 33 are identical. Each secondary coil 332is connected in parallel with an output 34 of the medium frequencysupply module MF. A respective one of the silicon rods or thin siliconrods R1, R2, R3, R4 is connected to each of the outputs 34. Each of tworespective outputs 34 at linked with one another. These are the outputs34 which receive a voltage from the same transformer 33, meaning thattwo taps of the secondary coil 332 are each connected with a respectiveterminal 341, 343, and 344, 346. The other two taps of the secondarycoil 332 are each connected with a respective node 351 and 352. Thenodes 351 and 352 are connected to the terminals 343 and 345. Thesecondary coil 332 of each transformer 32 can also be replaced by asecondary-side coil with a center tap located exactly at the center ofthe secondary coil of the transformer.

The magnitude of the voltage drops across the secondary coils 332 ofeach transformer 32 is identical. However, the voltages have theopposite polarity, because the winding sense of the two secondary coils332 of each transformer 32 is reversed. Linking the outputs 34associated with one transformer 32 results in a zero voltage dropbetween the terminals 341, 343, and 344, 346, respectively. Because theterminals 343, 344 are connected to each other at least via anelectrically conducting connection between the silicon rods or thinsilicon rods R2 and R3, there is also no voltage drop between theterminals 341 and 346 of the outputs 34 of the medium frequency supplymodule MF. Accordingly, zero current is supplied from the mediumfrequency module MF to the basic supply module B during the paralleloperation with the basic supply module B, although the terminals 341 and346 are connected to the terminals 131 and 132, respectively, of thebasic supply module.

However, a current may still be supplied from the basic supply module Binto the medium frequency supply module MF. This can be prevented byarranging between the coils on the secondary side of the transformers 32and the terminals 341, 343, 344 and 346 a capacitor 36 which filters,i.e. blocks, the low-frequency current provided by the basic supplymodule. As a result, the medium frequency supply module MF is decoupledfrom the basic supply module B.

The three illustrated modules B, MV, MF are configured so that they canbe operated independent from one another and that one module is notrequired for the other module. All modules have dedicated mainsconnections.

In addition to the mains connections for supplying power illustrated inthe Figure, the auxiliary current supplies are separate from oneanother. The connections via the interface and a communication bus (notillustrated) to the unillustrated control module are also independentfrom one another.

1. A power supply arrangement for reactors for producing polysilicon,the power supply comprising a central control unit and at least onebasic supply unit, the control unit comprises at least one controllerfor controlling and/or regulating the basic supply unit, the basicsupply unit comprises at least one input for supplying the basic supplymodule with electric energy, at least one output for connecting to agroup of loads which can be supplied with electric energy from the powermains via the basic supply unit, and controllable switches, which areconnected at least indirectly to the input and at least indirectly tothe output and which are configured for adjusting the energy to besupplied to the loads via the output, wherein the switches can becontrolled by the control unit, wherein the control unit is a controlmodule and the basic supply unit is a basic supply module, the controlmodule includes an input for connection to the power mains for supplyingthe control module with electric energy, the power supply arrangementincludes a communication bus, and both the control module and the basicsupply module include an interface configured for connecting the controlmodule and the basic supply module to the communication bus.
 2. Themodular power supply arrangement according to claim 1, wherein themodular power supply arrangement comprises a transformer with severalsecondary-side taps.
 3. The modular power supply arrangement accordingto claim 2, wherein the taps of the transformer are each associated witha corresponding input of the basic supply module and a group of thecontrollable switches is associated with each input of the basic supplymodule for adjusting the electric energy to be received via this input.4. The modular power supply arrangement according to claim 3, whereinthe groups of the controllable switches are connected to the inputs andto the output of the basic module without interconnection of additionalswitches.
 5. The modular power supply arrangement according to claim 4,wherein a node is arranged between the groups of the controllableswitches and the output, wherein the node can be connected via anadditional controllable switch to a reference potential.
 6. The modularpower supply arrangement according to claim 1, wherein the modular powersupply arrangement comprises several identical or similar basic supplymodules.
 7. The modular power supply arrangement according to claim 1,wherein the modular power supply arrangement comprises a medium voltagesupply module, which comprises at least one input for connection to apower mains supplying electric energy or for connecting transformedinputs and outputs for connection to one corresponding load from thegroup of loads, which optionally is being supplied with electric energydrawn from the power mains via the transformer, and an interfaceconnecting the modular power supply arrangement to the communicationbus.
 8. The modular power supply arrangement according to claim 6,wherein the medium voltage supply module comprises at least oneconverter for increasing a voltage to be applied at the input.
 9. Themodular power supply arrangement according to claim 7, wherein acorresponding converter is associated with each output of the mediumvoltage supply module.
 10. The modular power supply arrangementaccording to claim 6, wherein a linked voltage across the outputs isequal to about 0 V at least when the loads connected to the outputs ofthe medium voltage supply module are supplied with power.
 11. Themodular power supply arrangement according to claim 1, wherein themodular power supply arrangement comprises a medium frequency supplymodule which comprises at least one input for connection to a powermains for supplying electric energy and outputs for connection to acorresponding load from the groups of loads, which load can be suppliedwith electric energy received from the power mains, and an interfaceconnecting the power supply arrangement with the communication bus. 12.The modular power supply arrangement according to claim 10, wherein themedium frequency supply module comprises one or more frequencyconverters for increasing the frequency of a voltage of the power mainsapplied at the input.
 13. The modular power supply arrangement accordingto claim 11, wherein a corresponding output of one of the frequencyconverters is associated with each output.
 14. The modular power supplyarrangement according to claim 10, wherein the linked voltage across apair of outputs of the medium frequency supply module is equal to about0 V at least when the loads connected to the outputs of the mediumfrequency supply module are supplied with electric power.
 15. Themodular power supply arrangement according to claim 10, wherein twocorresponding terminals are associated with each of the outputs of themedium frequency supply module, with each pair of outputs having twoouter terminals and one inner terminal, wherein the outer terminals areassociated with a corresponding one of the two outputs of the pair ofoutputs and the inner terminal is associated with two outputs of thepair of outputs.
 16. The modular power supply arrangement according toclaim 10, wherein a three-phase AC voltage of 200 V to 600 V is beingsupplied to the input of the medium frequency supply module, for examplefrom a transformer.
 17. The modular power supply arrangement accordingto claim 10, wherein the modular power supply arrangement comprisesseveral identical or similar medium frequency supply modules.
 18. Themodular power supply arrangement according to claim 10, wherein thenumber of the medium frequency supply modules corresponds to the numberof the basic supply modules.
 19. The modular power supply arrangementaccording to claim 1, wherein the power supply arrangement comprisescontrol cabinets, and the control module, each basic supply module andoptionally each medium frequency supply module are arranged in acorresponding control cabinet.
 20. The modular power supply arrangementaccording claim 19, wherein each medium voltage supply module togetherwith a basic supply module is arranged in a control cabinet.
 21. Themodular power supply arrangement according to claim 19, wherein eachcontrol cabinet comprises a connection to the power mains.
 22. Themodular power supply arrangement according to claim 1, wherein eachmodule has a connection to an auxiliary power supply.
 23. The modularpower supply arrangement according to claim 19, wherein each controlcabinet has a display unit, in particular a display screen.
 24. Themodular power supply arrangement according to claim 4, wherein theadditional switches are mechanical switches such as contactors.
 25. Themodular power supply arrangement according to claim 7, characterized inthat the medium voltage supply module comprises at least one converterfor increasing a voltage to be applied at the input.
 26. The modularpower supply arrangement according to claim 16, wherein the three-phaseAC voltage is about 400 V.
 27. The modular power supply arrangementaccording to claim 20, wherein each control cabinet comprises aconnection to the power mains.
 28. The modular power supply arrangementaccording to claim 1, wherein the controllable switches are thyristors.